From mantle geodynamics to environmental processes: a geochemical perspective

现代地球化学致力于量化和解释元素在地球不同的主要地质储集层内部和之间的转移，包括地幔、地壳、海洋和大气。地球化学为从根本上理解我们的星球提供了答案和工具，包括环境、全球变化、资源、人类健康和自然灾害。这种研究需要对岩石、矿物、水或有机物中的同位素比率和元素浓度进行精确的分析。多收集器电感耦合等离子体质谱仪极大地扩展了可测量的潜在同位素系统，并实现了前所未有的灵敏度和精确度。我建议研究地球化学应用的三个主要主题：1)地幔和固体地球，2)环境影响，3)质谱学的分析发展。由于地球深部不能直接取样，地球化学家依靠分析玄武岩来推断地幔的组成。我建议研究两个最大的现代地幔热柱(夏威夷和科尔盖伦)，它们起源于地幔深处，以及喀斯喀特弧形火山和沉积物，以模拟进入地幔的循环量。这一研究结果将有助于全球了解地幔中各组分的组成和分布及其随地质时间的变化。在环境主题中，我将使用重稳定同位素系统(Cd、Zn、Si和Pb)来研究海洋和陆地系统中的元素循环和金属污染。这项工作将增加我们对古代气候和海洋条件的了解，并对不列颠哥伦比亚省的渔业和水产养殖业产生影响。第三个主题的研究包括系统研究，以确定标准物质的特征和确定质谱学过程中有问题的基质效应。这项工作将为科学界提供一个宝贵的参考数据库和方法。拟议的五年研究方案的总体目标是通过使用同位素地球化学中的新分析可能性来评估地球及其环境的地球化学演化。

Modern geochemistry is concerned with quantifying and explaining the transfer of elements within and between the different major geological reservoirs of the Earth, including the mantle, the crust, the oceans, and the atmosphere. Geochemistry provides answers and tools for the fundamental understanding of our planet, including the environment, global change, resources, human health and natural hazards. Such research requires precise analysis of isotopic ratios and elemental concentrations in rocks, minerals, water, or organic matter. Multiple collector inductively coupled plasma mass spectrometers dramatically expand the potential isotopic systems that can be measured and allow for unprecedented sensitivity and precision. I propose to investigate three main themes of geochemical applications: 1) Earth's mantle and solid earth, 2) environmental impact, and 3) analytical developments in mass spectrometry. As the Earth's deep interior cannot be sampled directly, geochemists rely on analyzing basalts to infer the composition of the mantle. I propose to study two of the largest modern mantle plumes (Hawaii and Kerguelen) that originate in the deep mantle and, as well as Cascade Arc volcanoes and sediments to model the amount of recycling into the mantle. The results of this research will contribute to the global understanding of the composition and distribution of components in the mantle and their variation over geologic time. In the environmental theme, I will use heavy stable isotope systems (Cd, Zn, Si coupled with Pb) to investigate element cycling and metal pollution in marine and terrestrial systems. This work will increase our understanding of ancient climates and oceanographic conditions and has implications for British Columbia fisheries and aquaculture industry. Research within the third theme includes systematic studies to characterize reference materials and identify problematic matrix effects during mass spectrometry. This work will lead to an invaluable reference database and methodology for the scientific community. The overall objective of the proposed 5-year research program is to evaluate the geochemical evolution of our planet and its environment through the use of new analytical possibilities in isotopic geochemistry.